Calcium oxide

Health surveillance data

Administrative data

Endpoint:

health surveillance data

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Study period:

no data available

Reliability:

other: high

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Well-documented study on respiratory symptoms and ventilatory function among workers exposed cement dust. Local effects in the respiratory tract following inhalation of lime dust are attributed to the alkaline reaction of lime in contact with water (in this case the humidity of mucous membranes). Addition of water to cement or Portland cement can raise the pH to values exceed 13, thus giving a more alkaline mixture than that from CaO and Ca(OH)2. Since pH change is the primary adverse effect leading to irritation of the mucosa and impaired ventilatory function, (Portland) cement can be used as a surrogate to predict effects and safe exposure levels for lime. The following additional information should be considered: (Portland) cement contains hexavalent chromium which is, however, not contained in lime at significant concentrations. Until the addition of ferrous sulphate became a common procedure, cement contained about 5-10 mg Cr(VI)/kg of cement; a content of 20 mg Cr(VI)/kg has also been reported . After the addition of ferrous sulphate, the level of Cr(VI) decreased to less than 2 mg/kg. This reasoning was also used by the Scientific Committee on Occupational Exposure Limits (SCOEL) in their recommendation occupational exposure limits for calcium oxide (CaO) and calcium hydroxide (Ca(OH)2) (see 7.5.3, Repeated dose toxicity: inhalation). The current paper was considered by SCOEL for establishing the STEL and the 8 h TWA OEL for lime, employing read-across from (Portland) cement to lime.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

publication

Title:

Respiratory symptoms and ventilatory function in workers exposed to portland cement dust

Author:

Fell, A.K.M.; et al.

Year:

2003

Bibliographic source:

J. Occup. Environ. Med. 45, 1008-1014

Materials and methods

Study type:

health record from industry

Endpoint addressed:

repeated dose toxicity: inhalation

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

Controlled cross-sectional study on respiratory system effects of Portland cement workers.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Portland cement dust

IUPAC Name:

Portland cement dust

Details on test material:

- Name of test material (as cited in study report): Portland cement dust (mixture of 60-67 % CaO, 17-25 % silicon oxide, 3-8 % aluminium trioxide, 0-5 % ferric oxide); aerodynamic diameter = 0.05-5 µm
No further details are given.

Method

Type of population:

occupational

Ethical approval:

not specified

Details on study design:

The cohort for analysis consisted of 119 male workers from the largest cement plant in Norway and 50 workers from a nearby control plant, born 1918 to 1938. The mean age was 69.3 ± 5.8 and 68.8 ± 5.7 years for the exposed workers and control subjects, respectively. The mean duration of cement exposure was 21.8 ± 13.8 years.
In 1999, 20 person-related dust measurements were conducted. Mean concentration for total dust was 7.9 mg/m³ (SD = 12.9) and for respirable dust 0.91 mg/m³ (SD = 0.55). Ranges were 0.4 to 53.7 and 0.0 to 2.3, respectively.
All workers performed spirometry and gave information on respiratory symptoms in 1998 and 1999. Information on the occupational history and smoking profile for each subject was obtained by an investigator.
The forced vital capacity (FCV), forced expiratory volume in 1 sec (FEV1), and ratio of forced expiratory volume to vital capacity (FEV1/FVC) were measured. Data were analysed by multiple linear regression with adjustments for the predictors: age, height, and life-dose of tobacco and asbestos exposure.

Results and discussion

Results:

The prevalence of symptoms (cough, phlegm, different kinds of dyspnoea, wheezing, and upper airway infections) and mean pulmonary function indices were similar for exposed workers and controls. There was no dose-related increase in symptoms or decrease in lung function indices.
The prevalence of chronic obstructive pulmonary disease (COPD) was 14.3 % in the exposed group and 14.0 % among the controls.

Applicant's summary and conclusion

Conclusions:

The findings do not support the hypothesis that cement dust exposure has a negative impact on lung function or gives an increase in respiratory symptoms.
This study was used by SCOEL for establishing OELs for lime dust. Data on Portland cement as a surrogate were used as supportive information, based on the reasoning of similar pH, being the causative factor for respiratory effects in both lime and Portland cement dust, and overlap in substantial composition.